JPH0557346B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention relates to an aluminum alloy with excellent wear resistance and extrudability. [Prior Art] In general, aluminum has low hardness and poor wear resistance, so various alloying components have been conventionally added to aluminum to increase its hardness and improve its wear resistance. For example, JIS H4140 1.10 to 13.5 for 4032 aluminum alloys specified in
By adding a large amount of Si (by weight%), hard Si particles are dispersed in the aluminum, increasing its wear resistance. [Problems to be solved by the invention] However, although the above-mentioned high-Si content aluminum alloy has excellent wear resistance, it has poor extrudability, so it is particularly difficult to manufacture pipes etc. by porthole extrusion. Furthermore, since the hardness of the Si particles is extremely high, when cutting such aluminum alloys, the tool wear is severe, and the Si particles fall off on the finished surface, resulting in roughness of the cut surface. In addition to this, there was a problem that the machinability was generally poor, and the corrosion resistance was also impaired due to the large amount of Si particles dispersed in the Al. [Findings based on research] In view of the above-mentioned circumstances, the present inventors have conducted various studies and found that (1) the Si content in the high Si-containing Al alloy is 1.6 to 4.9;
When the Mg content is increased from 1.9 to 7.6% by weight, the extrudability and corrosion resistance of the Al alloy improves due to the decrease in Si content, and most of the Si is converted to Mg ₂ Si. (2) to form an intermetallic compound containing Si and Mg as described above, and to disperse this Mg ₂ Si in Al to prevent a decrease in wear resistance due to a decrease in the Si content; in Al alloy
When 0.5 to 1.5% by weight of Mn is contained, this Mn forms an Al-(Mn, Fe)-Si intermetallic compound (α phase) including Fe, which will be described later, and this α phase is dispersed in Al. In other words, in combination with the above (1), by reducing the amount of Si particles dispersed in high-Si content Al alloy, The extrudability and corrosion resistance of the alloy are improved, while by increasing the amount of Mg and adding Mn,
Mg ₂ Si and Al-(Mn,Fe)-Si based compounds are formed, and these intermetallic compounds are dispersed in Al to compensate for the decrease in wear resistance that would occur due to the reduction of the Si particles. As a result, the Al alloy modified in this way has excellent extrudability while maintaining wear resistance comparable to the high-Si content Al alloy. (3) The above-mentioned amounts of Si, Mg and Contains Mn
In addition, Fe: 0.3 to 1.0%, Cr: 0.03 in Al alloy
~0.25%, Zr: 0.05~0.25% and V: 0.03~
When one or more of 0.25% (all % means weight %, unless otherwise specified, all % means weight %), these components, like the above-mentioned Mn, and Si to form the Al-(Mn, Fe)-Si based intermetallic compound, and these compounds are dispersed in Al,
further improving the wear resistance of the Al alloy; (4) an Al alloy containing the amounts of Si, Mg, and Mn;
or further contains one or more of Fe, Cr, Zr and V in the above amounts.
Al alloy, Cu: 0.05~0.5% and Zn: 0.25~
When one or two of 1.5% is added,
We have discovered that the strength of these Al alloys can be increased. [Means for Solving the Problems] This invention was invented based on the above knowledge, and is an aluminum alloy that has excellent wear resistance and extrudability, and has less wear of the cutting tool and less shedding of hard particles during cutting. Contains Mg: 1.9~7.6%, Si: 1.6~4.9%, Mn: 0.5~1.5%, and further contains Fe: 0.3~1.0%, Cr: 0.03~ as necessary. 0.25%, Zr: 0.05-0.25%, V: 0.03-0.25%, one or more of the following, and Cu: 0.05-0.5%, Zn: 0.25-1.5%, one or two of the following. and the rest
The present invention relates to an aluminum alloy with excellent wear resistance and extrudability, characterized by having a composition consisting of Al and inevitable impurities. Next, the reason for limiting the component composition range as described above in this invention will be described. (1) Mg The Mg component has the effect of increasing the strength of the Al alloy by forming a solid solution in the Al alloy, thereby increasing the deformation resistance during extrusion of the Al alloy, but by coexisting with Si, most of the forms an intermetallic compound that becomes Mg ₂ Si, so it does not impair its extrudability;
Mg ₂ Si contributes to improving the wear resistance of Al alloys. In the Al alloy of this invention, the amount of Mg contained in it is 1.9 to 7.6%, so the following
When combined with the Si content: 1.6% to 4.9%, the Mg ₂ Si content becomes 3% to 12%, and some excess Si is included in a form other than Mg ₂ Si. If the Mg ₂ Si content is less than 3%, sufficient wear resistance cannot be obtained, while if it exceeds 12%, Mg ₂
Since Si crystallizes and impairs the extrudability and machinability of the Al alloy, the Mg content was set at the above 1.9 to 7.6%, which corresponds to the Mg ₂ Si content: 3 to 12%. (2) Si As mentioned above, the Si component combines with Mg to form Mg ₂ Si
This Mg ₂ Si particle forms an intermetallic compound called
In addition to imparting wear resistance to Al alloys, free
Unlike Si particles, it does not impair the corrosion resistance of the Al alloy, and after forming Mg ₂ Si, the remaining Si component can be mixed with Al, Mn, or the following.
It combines with any one or more of Fe, Cr, Zr, and V to form, for example, an Al-(Mn, Fe)-Si-based intermetallic compound (α phase), and this α phase is also contained in Al. Disperses to improve the wear resistance of the alloy. Therefore, in this invention, the Si content is determined by considering the Mg ₂ Si amount mentioned in the Mg section, the Si amount necessary to form this α phase, and the Si amount that does not form free Si particles. was set at 1.6% to 4.9%. (3) Mn As mentioned above, the Mn component is a component that combines with Al and Si and helps form the α phase that contributes to improving wear resistance, but if its content is less than 0.5%, the wear resistance No effect on sexual improvement, and it is only 1.5%
If the
Its content was set at 0.5-1.5%. (4) Fe, Cr, Zr and V Fe, Cr, Zr and V components, like Mn, all combine with Al and Si to form intermetallic compounds, thereby further improving the wear resistance of the Al alloy. It is added as necessary because it has an improving effect, but its content is 0.3%, 0.03%, 0.05% and 0.03% respectively.
If it is less than 1.0% for Fe, Cr,
If Zr and V exceed 0.25%, they will form huge primary crystal compounds and deteriorate the machinability and elongation of the alloy. 0.03-0.25% for Cr and V, and for Zr
It was set at 0.05-0.25%. (5) Cu and Zn Cu and Zn components are solid dissolved in Al and have the effect of increasing its strength, so they are contained in the alloy of this invention as necessary, but these contents are
If it is less than 0.05% for Cu and less than 0.25% for Zr, sufficient effect will not be obtained for the above action, while on the other hand, if it exceeds 0.5% for Cu, the corrosion resistance of the Al alloy will be impaired.
When Zn exceeds 1.5%, the surface finish of the Al alloy deteriorates during cutting.
The content of these components is
0.05 to 0.5%, and 0.25 to 1.5% for Zn. In addition, in the Al alloy of the present invention, after casting, the casting structure is homogenized, Mg, Si components, etc. are dissolved, Mg ₂ Si compounds are spheroidized, and Al-(Mn,
This process promotes fine precipitation of Fe)-Si compounds.
In order to reliably impart the desired wear resistance, extrudability and strength to the Al alloy, it is necessary to perform homogenization treatment, and if the temperature of this homogenization treatment is less than 400°C, the above effects will not be sufficiently obtained. On the other hand, if it exceeds 575°C, there is a risk of partial eutectic melting, so this temperature should generally be between 400 and 575°C. In addition, when processing the Al alloy of this invention into various parts by extrusion, this extrusion process is performed at 350°C.
If it is carried out at a temperature other than ~550℃, surface cracks will occur during extrusion, and if the degree of extrusion is less than 75%, the compression of casting defects such as cavities and pinholes in the ingot will not be sufficiently crimped. In addition, these defects remain after extrusion and deteriorate the mechanical properties of the product and the surface quality after cutting. This extrusion process is carried out at a temperature of 350-550℃ and an extrusion degree of more than 75%. There is a need. [Example] Next, the present invention will be explained by referring to an example while comparing with a comparative example. Invention Al alloys 1 to 13 having the component compositions shown in Table 1, Comparative Al alloys 1 to 8 having compositions outside the scope of the present invention (deviating components are indicated by * in Table 1), After casting billets with a diameter of 200 mm from the molten metal of a conventional Al alloy corresponding to the JIS 4032 high-Si content Al alloy, these billets were subjected to a homogenization treatment at a temperature of 560°C for 6 hours. Then, each billet was extruded into a round bar with a diameter of 36 mm at a temperature of 500°C. Next, after tensile straightening these round bars, the temperature: 530
It was held at 180°C for 1 hour for solution treatment, then water quenched, and then subjected to T6 treatment at 180°C for 8 hours. During the above extrusion, the maximum extrusion speed at which a round bar could be extruded without causing cracks on the surface of the extruded product was measured, and the extrudability of each of the alloys was evaluated based on this. In addition, in order to evaluate the wear resistance of the present invention Al alloy, the comparative Al alloy, and the conventional Al alloy, test pieces were prepared from the round bars made of these alloys, each having a cylindrical shape having a diameter of 4 mm at the contact surface. These pins were tested using a pin/disc type abrasion tester at a contact pressure of 300
The amount of wear on each pin was measured by pressing it against a rotating FC25 cast iron disk ^for 100 minutes at a friction speed of 1250 m/min.

【table】

〔Effect of the invention〕

From the results shown in Table 1, the present invention Al alloy 1
~13 all have high maximum extrusion speeds, low wear, and small bite wear, whereas Comparative Al Alloy 1 has too much Mg and Si, so the wear is large, and Comparative Al Alloy 2 has too much Si. Even if there is a sufficient amount of Mg, the wear resistance is still poor because the amount of Mg is too small. Comparative Al alloy 3 has too much Mg, so extrudability is poor and tool wear is significant.
In Al alloy 4, the amount of wear is large because the amount of Si is too small, in comparative Al alloy 5, the amount of Si is too large, resulting in severe bite wear, and in comparison Al alloy 6, the amount of wear is large due to the amount of Si.
Comparative Al alloy 7 has low wear resistance due to a lack of Mn, and comparative Al alloy 8 has too much Mn, resulting in severe tool wear. It can be seen that it is intense. As is clear from the above description, the present invention not only has excellent extrudability but also has excellent wear resistance that is comparable to or better than conventional high-Si content Al alloys. It is possible to provide an Al alloy suitable as a material for sliding parts such as pneumatic cylinders and hydraulic cylinders that particularly require such properties.

Claims (1)

[Scope of Claims] 1 Contains the following: Mg: 1.9 to 7.6%, Si: 1.6 to 4.9%, Mn: 0.5 to 1.5%, and the remainder is Al and unavoidable impurities (weight %). An aluminum alloy with excellent wear resistance and extrudability. 2 Contains Mg: 1.9 to 7.6%, Si: 1.6 to 4.9%, Mn: 0.5 to 1.5%, and further contains Fe: 0.3 to 1.0%, Cr: 0.03 to 0.25%, Zr: 0.05 to 0.25%, V: 0.03 to 0.25%, containing one or more of the following, and the remainder consisting of Al and unavoidable impurities (weight %), and has excellent wear resistance and extrudability. Aluminum alloy. 3 Contains Mg: 1.9 to 7.6%, Si: 1.6 to 4.9%, Mn: 0.5 to 1.5%, and further contains one or two of Cu: 0.05 to 0.5%, Zn: 0.25 to 1.5%, contains and the rest
An aluminum alloy with excellent wear resistance and extrudability, characterized by having a composition (weight %) consisting of Al and unavoidable impurities. 4 Contains Mg: 1.9-7.6%, Si: 1.6-4.9%, Mn: 0.5-1.5%, and further contains Fe: 0.3-1.0%, Cr: 0.03-0.25% Zr: 0.05-0.25%, V: 0.03 ~0.25%, one or two or more of the following, Cu: 0.05~0.5%, Zn: 0.25~1.5%, containing one or two of the following, and the rest:
An aluminum alloy with excellent wear resistance and extrudability, characterized by having a composition (weight %) consisting of Al and unavoidable impurities.